Safety device



Jan. 2, 1951 A. J. SMITH ET AL.

SAFETY DEVICE Filed Dec. 30, 1946 "lll- Iill NOTIFY 35 DEALER WHEN THESE WORDS SHOW mmm m mm n wmv, Mw, mw

Patented Jan. 2, 1951 UNITED STATES PATENT OFFICE SAFETY DEVICE Arthur J. Smith, Independence, Mo., and Gwynne Raymond, Oklahoma City, Okla., assignors to Black, Sivalls & Bryson, Inc., Kansas City, Mo., a corporation of Delaware Application December 30, 1946, Serial No. 719,328

14 Claims.

a leal: around the periphery thereof or through y pin holes in the diaphragm that result from corrosion or other causes.

It is, therefore, a principal object of the present invention to provide a safety device Which includes an auxiliary or signal diaphragm in combination with the main frang-ible diaphragm to serve as a protector for the main frangible element and to indicate leakage thereof if leakage occurs.

Other objects of the invention are to provide the protecting diaphragm with hidden indicia that are rendered visi-ble upon leakage occurring through or past the main frangible element, and to provide a protecting or signal diaphragm of different material than the main frangible element for protecting the main element from corrosion.

In accomplishing these and other objects of the present invention, we have provided improved structure, the preferred form of Which is illustrated in the accompanying drawing Where- Fig. 1 is a perspective section of a safety device embodying the features of the present invention.

Fig. 2 is a plan view of the safety device.

Fig. 3 is a fragmentary section with the auxiliary or protector diaphragm illustrating functioning thereof to indicate leakage of the main frangible diaphragm of the safety device.

Referring more in detail to the drawing:

I designates a safety device which is adapted for attachment to a part of a pressure system that must be protected against occurrences of sudden pressure differentials and which is made subject to the pressure in the system through a d-uct 2. The duct 2 is shown in the drawings as being provided with external threads 3 for mounting the safety device. The safety device includes a housing 4 having a substantially bowl-shaped body portion 5 including an annular flange 6 at its base and an open top, the flange 6 being internally threaded as at 1 to receive the external threads 3. The flange may also be externally threaded as at 8 so that it is adapted for mounting in an internally threaded duct or fitting if desired.

The housing 4 extends. upwardly and outwardly from the flange 6 and has an internal beveled annular seat or gripping face 9 encircling a flow opening l therethrough. The housing 4 includes a rim portion Il that extends outwardly from the seat 9 and is provided with substantially V-shaped annular groove l2 encircling an annu-V lar rib I3 having a rounded edge ld terminating in an outwardly tapered annular seat I5 sloping oppositely to the seat 9. The rim of the housing is internally threaded above each of the respective seats as at I8 and I7.

it designates a main frangible element or diaphragm that normally closes the flow opening l0 but which is adapted to fracture under excessive pressure differential. The diaphragm I8 is formed of a suitable material which is preferably shaped to provide a dome i9 of uniform thickness and capable of fracturing from pressure acting upon the concave side. The dome-shaped portion l9'of the diaphragm terminates from a smoothly rounded annular bend 2U into an outwardly flaring annular flange 2l which engages the seat'9 and is retained thereon by a clamping ring 22. The clamping ring encircles the dome portion ofthe diaphragm and has an inner diameter substantially corresponding .to that of the flow opening-'lll and an outer periphery forming a tapered seating or clamping face 23 that engages the inner side of the iiaring flange 2l of the frang-ible diaphragm. The ring 22 has an exterior diameter to pass the threads i6 and has a substantially flat face 2li engaged by a. ring 25 that is provided with circumferential threads 26 engaging the threads I6. The ring 25 has an innner diameter substantially conforming to the inner diameter of the ring 22 so as to form a continuation of the flow opening in case of rupture of the frangible element. The ring 25 is turned within the threads by means of a suitable spanner .wrench (not shown) to draw the ring 22 in clamping contact with the flaring flange of the diaphragm and to clamp the flange against the seat 9 so as to provide a leak-tight seal there between. If desired, the sockets 26 which are engaged by the socket wrench may be lled with a suitable material as indicated at 2l' to` prevent unauthorized removal of the retaining ring or tampering with the diaphragm.

As above pointed out, it is possible that leakage might occur between the seat 9 and flaring flange 2| of the diaphragm. that leakage may occur through pin holes that may appear in the diaphragm because of corrosion which would allow for slow escape of the pressure medium from the pressure system to It is also possible which the duct 2 is connected. In many instances, for example, in the case where the safety device is connected with a propane tank, such leakage is dangerous.

In order to avoid this diculty and to indicate when such leakage occurs, the present invention contemplates an auxiliary. frangible diaphragm 28. In the illustrated instance the aux iliary diaphragm 28 includes a substantially iiat disk-like portion 29 seated on the rounded portion of the rib I3 in covering relation with the dome portion of the main diaphragm. The auxiliary diaphragm also includes an outwardly fiar.-

ving flange 3S arranged reversely to. the flange 2-I of the main diaphragm for engaging directly the seat I and Which is retained in contact therewith by a wedge-shaped ring 3.I-. located in the groove I 2 and which has a beveled inner gripping face 32 engaging the outer face of the iiange' 30. The retaining ring is secured in contact with the Iiange and the` flange against the seat by a ring 3,3y vhaving exterior threads. 3.1i4 engaging the threads- II` previously described. The ring 3i!V encompasses the flat portion of` the auxiliary diaphragm whereby the uppersurface4 of the. dia.- phragml is completely exposed through the open top ofV the, housing to provide a, site on which indicia designated 35 are lettered intoV or. on. the diaphragm. This indicia. may include the command Notify the Dealer When These Words. Show and the word Dangerous The indicia are. then covered with an opaque.. coating 36 of brittle characteristic such as a brittlelacquer to conceal the indicia but which is adapted to. spall oi incidental to.. any bulging. of the diaphragm caused by leakage of the. main diaphragm or ac.- cumulation of pressure under the auxiliary diaphragm.. The, outer retaining ring; might also be provided with Spanner sockets 31 which are4 lled. with' suitable. material to prevent` unauthorizedremoval thereof after the-ring is in place.

Inassembling thesafety device-.themain frane. gible element or diaphragm. I8. isinserted within.

thehousing SQ that theiiange 2l thereon engages theseat 94 after which the ring 22 is placed there.-

oyer and. moved into. clamping. engagement.. upon. insertion of the threaded ring. 25 by meansof a. suitable Spanner Wrench. After thering 25. in. place. the. socket openings. for` the. wrench. are.l

filled; with. sealing. material, as` shown` in Eig; l.

The; auxiliary diaphragm 28 is then placed over.

the annular ribv I3 so that the. outwardly iiaring. flangethereof engages the seat I5. The. clamping. ring 3| is then. inserted into the. groove; and moved into clamping contact whenthe ring 33v is turned into the housing by meansofv a, Spanner` wrench or the like engageable with the socketf like recesses which are subsequently lled with.

sealing material.

givenpressure, a safety device havingtheproper.

diaphragms must be selected, that is, the sum of. thecalculated bursting pressures for the respecf; tive diaphragms substantially equal the desired.-

pressure at which the safety device is to function. For: example, assumingithat a safety device isto be.` used on`a propane tank to be. maintained at` 2 00. pounds working pressure, the pressure. at.

which the` safety deviceis to function should be around 400 pounds. Therefore, the main diaphragm selected may have a bursting pressure of 300 pounds andthe auxiliary orprotector. diaV phragm a bursting pressure after deformation of 100 pounds.

The diierential relationships of the bursting pressures of the diaphragms is for the reason iat should leakage occur through the main diaphragm as, for example, `through a minute pin hole or a minute leak around the anchoring flange of the diaphragm, the space between the main diaphragm and the auxiliary diaphragm might become lled with the pressure to equilibrium with the pressure in the vessel to the end that a sudden rise in pressure both diaphragms would be effective in series.

The sum of the. bursting pressure of the two diaphragms should not be greater than the elastic limit of any part of the propane tank or other equipment to which it is attached.

When the device is mounted on the duct 2 which connects with the mechanism to be protected, it is merely screwed thereon to close the duct and. subject the concave side of the main diaphragm to the pressure in the system.

In case of a leak through the main diaphragm, pressure will accumulate within the space between the respective diaphragms to eifect bulging of the auxiliary diaphragm. This bulging of the diaphragm will indicate that a dangerousI condition exists and to makethe warning more.. noticeable, the bulging cracks and shatters the. lacquer coating so that it spalls therefrom to exposethe indicia and definitely indicate that the mPlQPQlY' main diaphragm` isI defective or seated.

Incase sudden pressure should occur, the main-1 diaphragm will rupture at its predetermined indicated by the action of the auxiliary diag-- phragm, the defective, device may be removed and replaced with another.. Also, should` the da; phragms function to relieve pressure, the oldU safety device is removed and replaced with a factory-assembled unit.

It desired, the auxiliary diaphragm may be.

formed Vof a diierent material than the main, dial-1 phragm to serve. as precaution against corrosiqn.,

or other misbehavior of themain diaphragm.

From., the foregoing it is. obvious that. we have provided a safety device. of the f rangilcle diagphragm type wherein the main diaphragm is protected by an auxiliary diaphragm whichalso servesas an indicator means for disclosing dangerous conditions that may-exist in the main diag phragm.

What we claim and desire to secure. by Letters.,

Patent is.;

l. A safety device, including a main. frangible diaphragm, an. auxiliary diaphragm having, an, outer. face, means supporting said diaphragme in, spaced relation, said` auxiliaryn diaphragm being adapted to bulge responsive4 to pressure that may,I

accumulate inthespace betweensaid diaphragms,A

and a4 coating on the outer face of the auxiliary` diaphragm, saidcoating being of brittle charac.

teristic and capable of spalling. upon bulging of.

the auxiliary diaphragm.

2. A safety device including a, main frangible.

and an opaque coating covering said lettering and capable of spalling upon bulging of said diaphragm.

3. A safety device including a housing having a ilow passageway provided With an inlet and an outlet and having axially spaced diaphragm seats intermediate the inlet and outlet, a main `frangible diaphragm mounted on the seat'at the inlet of said passageway, means in the housing for clamping the diaphragm to said seat, an auxi iary diaphragm on the other diaphragm seat and having an outer face exposed through the outlet of said passageway, means in the housing for clamping the auxiliary diaphragm to said seat, and a coating on the outer face of said auxiliary diaphragm, said coating being of brittle characteristic and capable of spalling upon movement of the auxiliary diaphragm responsive to building up of pressure within the space between said diaphragms.

4. A safety device including a housing having a flow passageway therethrough and axially spaced diaphragm seats encircling the flow passageway, frangible diaphragms on the respective seats, means in the housing for clamping the diaphragms to said seats, one of said diaphragms having a face being exposed through an end of the passageway, and a coating on said diaphragm face, said coating being of brittle characteristic and capable of spalling upon movement of said diaphragm responsive to building up of pressure between said diaphragms incidental to leakage occurring in the other diaphragms.

5. A safety device including a housing having a flow passageway therethrough and axially spaced diaphragm seats encircling the flow passageway, frangible diaphragms mounted on the respective seats and having differential bursting pressures, means in the housing for clamping the diaphragms to said seats, said diaphragm of lowest bursting pressure having a face portion exposed through the flow passageway, and a coating on said face of the diaphragm of lowest bursting pressure, said coating being of brittle characteristic and capable of spalling upon movement of said diaphragm responsive to building up of pressure between said diaphragms occurring through leakage of the diaphragm of higher bursting pressure.

6. A safety device including a housing having a flow passageway therethrough and axially spaced annular seats tapering in opposite directions and of differential diameter, a main frangible diaphragm having a flaring flange mounted on the seat of smaller diameter, a clamping ring engaging the opposite side of said flange, a retaining ring having threaded connection with the housing for urging the clamping ring into contact with said flange and the flange against said seat, an auxiliary diaphragm having an oppositely flaring flange engaging the seat of larger diameter, a clamping ring for said iiange of the auxiliary diaphragm, a similar retaining ring for the last named clamping ring, and a coating on the auxi.iary diaphragm, said coating being of brittle characteristic and capable of spalling upon movement of the auxiliary diaphragm responsive to building up of pressure between said diaphragms.

7. A safety device including a housing having a iiow passageway therethrough and axially spaced annular seats tapering in opposite directions, and of differential diameter, a main frangible diaphragm having a `flaring flange mounted on the seat of smaller diameter, a clamping ring engaging the opposite side of said flange, a r-a taining ring having threaded connection with the housing for urging the clamping ring into contact with said iiange and the flange against said seat, an auxiliary diaphragm having an oppositely flaring flange engaging the seat of larger diameter, a clamping ring for said flange of the auxiliary diaphragm, a similar retaining ring for the last named clamping ring, and a coating on the auxiliary diaphragm, said coating being of brittle characteristic and capable of spalling upon movement of the auxiliary diaphragm responsive to building up of pressure between said diaphragms, said auxiliary diaphragm having indicia under said coating.

8. A safety device including a housing having a flow passageway therethrough and `axially spaced annular seats tapering in opposite directions and of differential diameter, a main frangible dome-shaped diaphragm having an annular outwardly flaring anchoring flange mounted on the dome side of said diaphragm and on the seat of smaller diameter, a clamping ring engaging the dome side of said anchoring flange, a retaining ring having connection with the housing for urging the clamping ring into contact with said anchoring iiange and the flange against said seat, an auxiliary diaphragm having an oppositely flaring flange engaging the seat of larger diameter, a clamping ring for said flange of the auxiliary diaphragm, a similar retaining ring for the last named clamping ring, and a coating on the auxiliary diaphragm, said coating being of brittle characteristic and capable of spalling upon movement of the auxiliary diaphragm responsive to building up of pressure between said diaphragms.

9. In a safety device, a frangible diaphragm, and a coating on the diaphragm, said coating being of brittle characteristic and capable of spalling upon bulging movement of the diaphragm responsive to building up of pressure on said diaphragm.

10. In a safety device, a frangible diaphragm, and a coating on the diaphragm, said coating being of brittle characteristic and capable of spalling upon bulging movement of the 'diaphragm responsive to building up of pressure on said diaphragm, said diaphragm having indicia under said coating.

11. A safety vdevice including a main frangible diaphragm having a rated bursting pressure and normally adapted to retain pressure below said rated pressure, a signal diaphragm, means supporting said diaphragms in spaced relation, said signal diaphragm being formed of a material capable of bulging under pressure acting thereon below said rated pressure of the frangible diaphragm whereby said signal diaphragm bulges responsive to any leakage of pressures by the frangible diaphragm which are lower than said rated bursting pressure, and a spallable material on the signal diaphragm for indicating bulging of the signal diaphragm.

l2. A safety device including a housing having a iiow passageway therethrough and axially spaced main and signal diaphragm seats encircling the flow passageway, a main frangible .diaphragm mounted on the main diaphragm seat and having a rated bursting pressure and normally adapted to retain pressures below said rated pressure, means in the housing for clamping the main diaphragm to its seat, a signal diaphragm on said other seat and formed of a material adapted to bulge under pressure acting 75 thereon below the rated pressure of the :frangible ciaphragniand a spall'abley mate-rial on= theA signal diaphragm for indicating bulging. off thev signal diaphragm.; andi means` in thehousing. for clamp.- ingfthe.y signal diaphragm. tosaid othendiaphragm seat.

13; A. safety. device. including a exible signal diaphragm adapted. to fi'ex Whena4 pressure: acts.

onor-:aside ofA the diaphragm, andia,suhstarzdsiali-1,"v

brittle coating on. the diaphragm; of@ 1essexi.

bility. than. the diaphragm. whereby said. coat,- ing. spalis under`A` iiexuxfeof the. diaplfn'agrn..v

1e. A safety.A device including a exibie signal diaphragm adapted td'ex. when a pizessni-.ev acts on one. side. of: .theL .diaphragm having. indicia thereon, and a coating on the. diaphragm and covering. the. indicia,` said; coating being of brittle characteristic and of. less. flexibilitythan the diaphragm. whereby said` coating spalla offiA telex.

pose saidz indicia` upon exure. of' the diaphragm.

ARTHUR J. SMITH.'l GWYNNE. RAYMOND.

REFERENCES. GITIED,y

Thel following referencesarer ofrecordY in the nie offv this` patent:

UNITED. STATES PATENTS Number NameV Date 568,680:V Henderson Sept. 29, 1896 1,535,536.. MacDonald Apr. 28;.1925 2,242,547.- Raymond May 20, 1941 2,261,035.. Miller Oct. 28, 1941 2,263,840 Franck .v,-- Nov. 25', 19.41' 2,381,353 Raymond ..k Oct. 23', 1945V 

